Return to zero mechanism of two chronograph counters



Feb.111,'197o G. DUBOIS 3,49 97 RETURN 1'0 ZERO MECHANISM'OF TWO CHRONOGRAPH COUNTERS Filed March 28; 1968 mvemoa Ge'ra/a 0030/5 ATTORNEY United States Patent US. Cl. 58-74 3 Claims ABSTRACT OF THE DISCLOSURE A zero mechanism for two chronograph counters comprising two return to zero hammers cooperating with a return to zero heart-piece associated with each of the counters, a return spring urging the hammers into their rest position an activating member for bringing these hammers into their operating position, two hammers are superimposed one of them being directly controlled by the actuating member and having a two-armed lever rotatably mounted thereon, one arm of the two-armed lever acts on the second hammer and the second arm is controlled by the action of the said return spring, by this arrangement the spring ensures not only the return to rest position of the hammers, but also ensures the elastic connection between the two hammers, thereby permitting that the hammer controlled by the action of the two-armed lever to first bear on its associated return to zero heartpiece, the displacement of the hammer directly controlled by the actuating member continuing until this hammer operates its associated return to zero heart-piece, a relative movement between two hammers being then possible, the force necessary for the return to zero of the first heart-piece being impelled to it by the return spring through the intermediary of the twoarmed lever.

The invention relates to a return to zreo mechanism of two chronograph hands which includes two return to Zero hammers elastically returned to rest position and submitted to the action of a control device for bringing them into their operating position.

This mechanism is characterized by the fact that the two hammers are superimposed, one being directly submitted to the action of the control device and carrying, rotatably mounted thereon, a two-armed lever, one arm of which acts on the second hammer and the second arm of which is submitted to the action of a return spring, the whole operating in such a way that the return spring not only effects the return of the hammers into their rest position but ensures the elastic connection between the two hammers, so that the hammer submitted to the action of the two-armed lever bears first upon its associated heart-piece, while the displacement of the hammer directly actuated continues until this hammer actuates the other heart-piece, with a relative movement between the two hammers then being possible, the necessary force for the return to zero of the first heart-piece being furnished by the said spring through the intermediary of the two-armed lever.

The drawing shows, by way of example, one embodiment of the invention.

FIGS. 1 and 2 are plan views of a return to zero mechanism of two chronograph hands, in the rest position in FIG. 1 and in the operating position in FIG. 2.

The return to zero mechanism is intended to effect the return to zero operation of a second counter 1 and of a minute counter 2 of a chronograph, these two counters being each provided with a heart-piece 3 and 4 respectively, for effecting their return to zero.

3,495,397 Patented Feb. 17, 1970 ICC The mechanism comprises two hammers 5 and 6 intended to act, respectively, on the heart-pieces 3 and 4 for returning the counters to zero. These two hammers 5 and 6 are superimposed and are rotatably mounted on a point 7 on the frame 8 of the mechanism. A columnwheel 9, driven by a pusher, not represented, produces the stopping and the starting of the chronograph. The return to zero of the counters is produced by a pusher, not represented, acting on the end part 10a of a rocking lever 10 guided by a pin 11, and a finger 10b of which engages a notch 12 provided in lower hammer 5.

The hammers are submitted to the action of a coil spring 13 hung on the one hand at 14 to the frame of the mechanism and, on the other hand, to the arm 15a, of a two-armed lever 15 pivotally mounted at 16 on hammer 5, and the second arm of which, designated by 15b, bears on hammer 6. This latter is provided with a circular aperture 17 traversed, with play, by a pin 18 carried by hammer 5.

The operation of the mechanism follows:

When column-wheel 9 occupies the position represented in FIG. 1, the counters are driven and the return to zero thereof is not possible, operation of the pusher controlling the movements of rocking lever 10 being prevented by the fact that an extension 5a of hammer 5 would then abut against one of columns 19 of wheel 9. The hammers are held in their rest position by spring 13 which acts directly on hammer 5 and indirectly on hammer 6, through the intermediary of pin 18 abutting against the lateral wall of opening 17. The two hammers are then held in their rest position by spring 13.

When column-wheel 9 occupies the position represented in FIG. 2, a push exerted on part 10a of rocking lever 10, along arrow 20, displaces the two hammers, by a direct action on hammer 5, which rotates the two hammers in the counterclockwise direction, against the action of spring 13, which is then wound.

The relative position of the hammers is such that hammer 6 abuts first on associated heart-piece 4. The movement of hammer 5 continues, owing to the play of pin 18 in opening 17, until this hammer has actuated heart-piece 3 and returned it to Zero. Thus, the arrangement is such that it permits a relative movement of the two hammers, one with respect to the other, to allow a correct return to zero of the two counters. It is to be noted that the force exerted by hammer 6 on heart-piece 4 is impelled to it by spring 13, by the intermediary of lever 15, so that the spring ensures two distinct operations, i.e., the return to zero of counter 2 and the return to the rest position of the two hammers.

What I claim is:

1. In a return-to-zero mechanism for two chronograph counters comprising: a return to zero heart-piece associated with each of the counters, two superimposed return-to-zero hammers, a return spring for urging the hammers into rest positions, a control device for bringing the hammers into operating positions, one of the hammers being directly controlled by the action of the control device, and a two-armed lever rotatably mounted on the directly controlled hammer, a first arm of the lever acting on the second hammer and a second arm of the lever being submitted to the action of the return spring, with the spring ensuing the return of the hammers to rest positions and the elastic connection between the two hammers for permitting the hammer submitted to the action of the lever to bear the first on its associated return to zero heart-piece, and with the displacement of the directly controlled hammer continuing until the hammer operates its associated return to zero heart-piece and thereby permitting a relative movement between the two hammers, the force necessary for the return to zero of the first heart-piece being impelled thereto by the spring through the intermediary of the lever.

2. In a mechanism as claimed in claim 1, an abutting device rendering the hammers rigid with each other when the first hammer is returned to its rest position by the spring and the second hammer is simultaneously returned to zero.

3. The mechanism as claimed in claim 1, including, a pin carried by one of the hammers and traversing an aperture in the second hammer for making the hammers rigid with one another when the first hammer is returned to its rest position by the spring and the second hammer is simultaneously returned to zero.

References Cited UNITED STATES PATENTS 4 FOREIGN PATENTS 480,951 7/1918 France. 914,593 6/1946 France. 479,380 3/ 1953 Italy. 161,894 8/ 193 3 Switzerland. 285,850 1/ 1953 Switzerland.

10 Feb. 21, 1957, Class 58, Sub. 74, 1 sht. dwg., 2 pp. spec.

RICHARD B. WILKINSON, Primary Examiner S. A. WAL, Assistant Examiner US. Cl. X.R. 235l44 

